The caliche, mallacán[1]​ or petrocalcic horizon, is a B horizon (or edaphic deposit) hardened or cemented of soluble calcium carbonate. This precipitates at depth, cementing other materials, such as sand, clay, gravel or silt.

Caliches can be found throughout the world, generally in arid or semi-arid regions such as in central and western Australia, the Kalahari Desert, the Sonoran Desert, the Atacama Desert, and the plateau of the Great Plains of the United States.

The Spanish term "caliche" comes from the Latin calx: cal "Lime (mineral)").

In English it is known as caliche, hardpan, calcrete or duricrust.

In India it is called kankar.

In northern Chile[2][3]​ and in Peru "caliche" refers to the richest deposits of nitrate salts in the Atacama Desert.[4]​

Caliche may also refer to clay deposits in Chile, Peru, Colombia and Mexico.

Additionally, it has been used to describe some forms of bauxite, chalcedony, kaolinite, quartzite, laterite, nitratine, and opal.